Automatic roof vent



Sept. 3, 1968 E. SHAPIRO AUTOMATIC ROOF VENT 2 Sheets-Sheet 1 Filed July 25, 1966 INVENTOR Eli Shapiro ATTORNEY Sept. 3, 1968 VESHAPIRO 3,399,500

AUTOMATI C ROOF VENT Filed July 25, 1966 2 Sheets-Sheet 2 ATTORNEY United States Patent 3,399,500 AUTOMATIC ROOF VENT Eli Shapiro, Garland, Tex., assignor to Plastic Products of Texas, Inc., Garland, Tex., a corporation of Texas Filed July 25, 1966, Ser. No. 567,667 4 Claims. (Cl. 52-1) ABSTRACT OF THE DISCLOSURE A roof vent construction comprising a lid pivotly attached at one ege to an upturned curb on the roof of a building, a raising means consisting of a long link, a short link, and a spring, one end of which is connected to the said short link and the other end of said spring is attached to the lid, with locking means including a fusible link which comes apart by exposure to a predetermined high temperature in such a manner as to open the said lid automatically to expel smoke from the building in case of fire. The spring in the opening linkage is positioned so that the center line of the spring always passes substantially through the pivot point of the lid to reduce a secondary torque acting on the lid opposed to the torque tending to open the lid as a result of the forces exerted on the links and the lid respectively.

Background of the invention This invention is concerned with a roof vent and is particularly concerned with improvements in that type of roof vent which is automatically opened in response to heat or pressure within a building.

This invention is particularly concerned with improvements in that type of automatic roof vent disclosed in my Patent No. 3,251,158, issued May 17, 1966, entitled, Automatic Roof Vent.

Certain shortcomings have become evident in the use of the automatic roof vent as disclosed in said patent, which are as follows:

In the device disclosed in said patent spring pressure is employed to exert force against the lid to open same by means of a long lever and a short lever. The force produced by such lever, spring arrangement is created by the spring pressure producing a torque, which torque is the product of the spring pressure multiplied by the normal distance between the center line of the spring and the pivot point of the long lever adjacent to the curb wall.

In the structure shown in said patent the end of the spring is secured in stationary position to the curb or housing of the roof vent and the outer end thereof is attached to the pivoted movable ends of the long lever and the short lever.

In such structure as the vent lid is lifted up after being released, the spring pressure decreases due to the spring becoming shorter, and simultaneously the torque also decreases in lifting effect until the lifting effect thereof becomes zero at the point when the center line of the spring coincides with, or is parallel to the center line of the long lever. At such point the spring exerts no lifting force tendin g to open the lid because no torque is created since the normal distance between the center line of the spring and the pivot point of the long lever adjacent the curb wall is equal to zero. Hence by definition no torque is created. At such point there is exact equilibrium. However, at such point the lid is not completely open. Normally the lid would continue to open due to inertia, but the spring tends to produce an opposite force as it is stretched, tending to close the lid.

It is apparent that under conditions such as snow load on the lid or wind pressure tending to close the lid of willcient force to overcome the inertia of the opening move- 3,399,500 Patented Sept. 3, 1968 "ice ment of the lid, the lid will not open completely to a position where it will be latched in open position. Therefore, the lid is subject to being either partially or fully reclosed by 'wind or weight produced by snow.

Brief summary of the invention The above mentioned defect has been overcome by the present invention wherein one end of the lifting spring is connectedto the lid instead of to the fixed curb so that the attach-ment point of the end of the spring moves with the lid whereby such attachment point is in a different location for each position of the lid as it opens. The attachment point of the end of the spring is so arranged with relationship to the hinge point of connection of the lid to the fixed curb, and is so arranged with relationship to the long lever and short lever as to cause the center line of the spring to pass through, or very close to, the transverse center line of the lid hinge pivot point in all lid positions from completely closed to completely open positions.

It will be noted that one end of the spring is attached to the vent lid and the other end is attached to the pivoted movable ends of the long lever and the short lever, the other end of the short lever being pivotally attached to the vent lid. When under tension the spring force acting through the short lever always tends to open the lid. It is preferable that the center line of the spring passes below or to the left of the lid hinge pivot point. If the center line of the spring passes above or to the right of the hinge pivot point it will tend to close the lid. Furthermore the greater the distance becomes between the center line of the spring and the lid hinge pivot point the greater the torque produced. Conversely, if the center line of the spring is above or to the right of the hinge pivot point the distance between them should be as small as possible to prevent the torque from negating or subtracting from the lifting force. As disclosed herein the center line of the spring passes below or to the left of the hinge pivot point and is adequately spaced therefrom to exert a continuous opening force to the lid when fully closed or fully open. However, it will be understood that the center line of the spring could pass from a position above the hinge pivot point and move to a position outwardly of said pivot point if the torque produced by such condition is substantially less'than the torque produced and acting through the short lever.

At complete open position of the lid the spring is still partially extended to exert a force against the short arm to cause the arm to hold the lid in open position, thereby preventing the lid from being closed by wind pressure.

It is therefore a primary object of the invention to provide in an automatic roof vent of the type indicated, a combination of lever arrangement, lever pivot point positions and lifting spring attachment and movement whereby the attached end of the spring moves with the lid as it is opened and the attachment point of the spring is so related to the hinge point of the lid that the center line of the spring passes through, or approximately through, the center line of the hinge pivot point as the lid opens, and continuous opening force is exerted by the spring through the short lever while the lid is being opened and after it is opened, urging it to open position.

A still further object of the invention is the attachment of the rubber bumper, engageable with the lifting arm, on the lid frame so that the shock force created by the opening of the lid is transmitted to the lid rather than to the curb wall which is made of relatively lighter material than the lid frame and has been found to cause damage thereto.

Other and further objects of the invention will become apparent upon reading the detailed specification hereinafter following and by referring to the drawings annexed hereto.

Brief description of the drawings A suitable embodiment of the invention is shown in the attached drawings wherein:

FIG. I is a top plan view of a typical roof vent;

FIG. II is a cross sectional elevational view taken on the line II-II of FIG. I;

FIG. III is a cross sectional elevational view taken on the line IIIIII of FIG. H;

FIG. IV is a cross sectional elevational view taken on the line IV-IV of FIG. 11;

FIG. V is a cross sectional elevational view taken on the line VV of FIG. II;

FIG. VI is a fragmentary cross sectional elevational view taken on the line VI-VI of FIG. II;

FIG. VII is an enlarged fragmentary cross sectional elevational view showing the hinge connection of the lid in relationship to the spring with the lid in full open position; and

FIG. VIII is a fragmentary cross sectional elevational view of the bumper and spring mounting bracket with spring attached thereto.

Description of a preferred embodiment Numeral references are employed to indicate the various parts shown in the drawings and like numerals indicate like parts throughout the various figures of the drawmg.

The numeral 1 indicates a rectangular housing or curb for the vent assembly, said curb having a laterally extending flange 2 thereon which is secured about an opening 3 in the roof 4 by means of suitable nails 5, or other attachment members.

A lid 6 is pivotally attached at one edge to the curb. The lid consists of a flat or oval shaped dome 6 which may be made of transparent material to admit light, or it may be opaque. The dome shaped member 6 is secured to a rectangular shaped inner frame 7.

A laterally outwardly extending flange 8 is provided about the frame member 7 which is terminated at its outer edge by a downwardly projecting lip 9. The dome retaining member has a serrated edge 10a thereon which is forced into engagement with the flange 6a of dome 6 and has a downwardly projecting lip 10d thereon which is secured to the lip 9 by means of interengaging channels 10b and is fixedly attached thereto by means of suitable metal screws 10c. The resilient seal strip 11 is positioned between the lateral extension 8 and the outwardly extending flange 6a on the dome cover 6.

A flashing member 12 is provided about the upper edge of the curb 1 about which insulation material 12a is provided.

An outwardly flared annular skirt 13 provides a flashing about the curb.

A resilient seal strip 14 is provided between the flashing member 12 and the lower surface of the extension 8.

The assembly hereinbefore described provides a weatherproof seal attachment of the roof vent and cover over and about the opening 3.

The hinge brackets 15, of which there are two, provide hinged attachment of the lid to the curb. The hinge brackets 15 are secured to the lid and are hingedly attached to hinge bar 17, secured to the housing, by means of pivot bolts 19. The hinge brackets 15 are secured to the lid by means of suitable screw 16.

The bell crank arm is pivotally attached by pivot bolt 21 to the side wall of the curbing 1, and has a shorterlateral arm 24 thereon which is engaged with a laterally extending flange 27 on the angled leg 26 provided on the bracket 25. The bracket is secured to the inner side of the lid frame 7 by suitable bolts or rivets 25a. I

A fusible link 28, which comes apart by exposure to a predetermined high temperature, is attached to the lower end of the arm 20 by means of S-hook 28a and is secured at its other end to the spring 20 by an S-hook 28b. The

other end of the spring 29 is attached to the curb 1 by a cord or cable 30 which is pivotally attached at 31 to the curb.

A manual release cord 32 is attached to the lower end of the arm 20 by an S-hook 32a. The release cord 32 extends through a pulley 33 which is mounted to the inner wall of the curb 1, and has a ring 34 attached to the lower end thereof which may be grasped for the purpose of manually releasing the lid to allow it to open. If desired the manual release cord 32 may be extended through the wall of the curbing above the roof of the building and may have a ring35 on the outer end thereof whereby the lid may be released manually from the roof, if desired.

The spring attachment brackets 36'are secured to the lid frame 7 by welding or other suitable means.

Long lifting'levers 39 have one end pivotally attached to brackets 40, secured to the curb 1, by means of pivot bolts 40a, and the other ends thereof are pivotally attached at their outer ends to the pins 41, and the upper ends of the short levers 42 are pivotally attached to the downwardly extending flanges of the support channels 44 secured to lid frame 7.

The springs 46 have their upper ends 46a hooked in appropriate holes 36a provided in the brackets 36, and the other ends 46b of the springs 46 are secured to the outer ends of the pivot pins 41.

As will be seen from FIG. VI the lifting lever and spring arrangement is duplicated in the assembly.

A rubber bumper 47 is secured to, and extends outwardly from, each bracket 36 and is in position to engage the lever arm 39 to limit the upward movement thereof and the extent of opening of the cover and the final position of, and. extension of, spring 46 and short lever arm 42, as shown in FIG. VH.

A plurality of adjustment holes 49 may be provided in the short levers 42 whereby the end of the spring 46 may be moved upwardly for the purpose hereinafter described.

The operation and function of the automatic roof vent assembly hereinbefore described is as follows:

In the event of a fire in the building on which the automatic vent is installed the temperature will increase sufficiently to melt and sever the fusible link 28 which releases the pressure on the lower end of the arm 20 exerted by the extended spring 29. This allows the force exerted by the extended springs 46 through the short levers 42 to pivot the arm 20 about the pivot point 21 to release the lateral arm 24 from the bracket 25 to allow the lid to open about the hinge pivot points 19.

The lid will also open as a result of predetermined pressure caused by explosion or collection of gas from combustion inside the building. When the pressure becomes great enough to extend spring 29 the opening action will occur the same as described above.

The lid may also be manually released for opening by grasping the rings 34 or 35 and pulling on the manual release cord or cable 32 sufficiently to overcome the spring 29.

The contraction of the springs 46 pivots the lever 39 upwardly in an arcuate movement as force is exerted against the short lever 42 to thereby push the lid upwardly in rapid movement. It will be observed that as the lid is raised the ends of the springs 46 move with the lid and the attachment points of the ends of the springs are so arranged that the axis of thespring is in alignment with the center line of the hinge points 19, or substantially in alignment at all positions of the spring as the lid moves upwardly. As indicated by the line A--A in FIG. VH, when the lid is fully open and the arms 39 have contacted the bumpers 47 to limit further opening movement, the axes of the springs 46 are in substantial alignment with the center line of the hinge pivot points 19 of the lid.

As indicated in FIG. II in broken lines, when the lid is fully open, the springs are still partially extended and exert a force on the short lever 42 to urge the lid to an open position, thereby assuring that the lid is positively urged to full open position as limited by the engagement of the arms 39 with the bumpers 47 and is positively held in such full open position against closing pressure which might be exerted against the lid from the outside.

It will be understood that other and further embodiments of the invention may be devised without departing from the spirit and scope of the appended claims.

I claim:

1. A roof vent construction comprising, a housing having side walls; a cover; a hinge attaching the cover to one of the side walls said hinge having a first hinge pivot point; lifting means to raise said cover including, a long lever arm having one end hingedly attached to a side wall at a second pivot point; a short lever arm hingedly attached at one end to the other end of the long lever arm at a third pivot point and hingedly attached at its other end to the cover at a fourth pivot point; and a spring having one end pivotally attached to the pivoted movable ends of the long lever and the short lever at the third pivot point and the other end thereof attached to the cover, said spring being normally extended at all positions of the cover between the closed and the open position of the cover, the axis of the spring being in substantial alignment with the first hinge pivot point and remaining in such alignment as the cover is raised about said first hinge pivot point by force produced by retraction of the spring.

2. The combination called for in claim 1 with the addition of a bumper member carried by the cover engageable with the long lever arm to limit the angular movement of the long lever arm and thereby the opening movement of the cover.

3. A roof vent construction comprising, a housing having side walls; a cover; a hinge attaching the cover to one of the side walls at a first hinge pivot point; lifting means to raise said cover including, a first lever arm having one end hingedly attached to a side wall at a second pivot point; a second lever arm, which is shorter than the first lever arm, hingedly attached to the other end of the first lever arm at a third pivot point and hingedly attached at its other end to the cover at a fourth pivot point; and a spring having one end pivotally attached to second lever arm and the other end thereof attached to the cover; said spring being normally extended at all positions thereof between closed and full open position of the cover; and the axis of the spring being in substantial alignment with the first hinge pivot point and remaining in such alignment as the cover is raised about said first hinge pivot point by retraction of the spring.

4. The combination called for in claim 3 wherein the point of attachment of the spring to the cover is initially located inwardly and below the first hinge pivot point and terminates at a point above and inwardly of the first hinge pivot point.

References Cited UNITED STATES PATENTS 2,827,003; 3/1958 Stetson 491 3,036,406 5/1962 Wasserman 497 1,144,899 6/1915 Gold 1680 1,223,408 4/ 1917 Loftsgaarden 16-80 3,251,158 5/1966 Shapiro 52-72 FRANK L. ABBOTT, Primary Examiner.

S. D. BURKE, Assistant Examiner. 

